A power converter is a circuit which converts current at one voltage to current at another voltage. Switching converters use one or more switches to effect this conversion. Converters that control the output voltage by using a constant “on” time for the switch(es) and varying the switching frequency are called frequency modulated converters. Resonant converters are converters that use inductive and capacitive (LC) reactive elements in resonance to transfer power from an input source to the output.
Design objectives of power converters include: maximizing power conversion efficiency from input to output; minimizing component count and cost; and minimizing stress on the various converter components to maximize reliability. Another important design objective is a monotonic power transfer function. The transfer function relates the output power of the converter to its control variable. For frequency modulated converters, the control variable is the switching frequency.